IN79001
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D. C. 20555
January 31, 1979
MEMORANDUM FOR: B. H. Grier, Director, Region I
J. P. O'Reilly, Director, Region II
J. G. Keppler, Director, Region III
K. V. Seyfrit, Director, Region IV
R. H. Engelken, Director, Region V
FROM: Norman C. Moseley, Director, Division of Reactor
Operations Inspection, OIE
SUBJECT: Information Notice No. 79-01, BERGEN-PATERSON
HYDRAULIC SHOCK AND SWAY ARRESTOR
The subject document is transmitted for issuance on February 2, 1979. The
Information Notice should be issued to all power reactor facilities with an
operating license or a construction permit. Also enclosed is a draft copy of
the transmittal letter. No inspection followup is necessary since no action
by the licensee is requested. We anticipate forwarding additional
information when the Rancho Seco evaluation program for corrective action is
completed.
Norman C. Moseley
Director
Division of Reactor
Operations Inspection, IE
Enclosures:
1. Information Notice No. 79-01
2. Draft Transmittal Letter
CONTACT: H. A. Wilber, IE
(492-8180)
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(Draft letter to all power reactor facilities with an operating license or a
construction permit)
Information Notice No. 79-01
Addressee:
This Information Notice is provided as an early notification of a possibly
significant matter. It is expected that recipients will review the
information for possible applicability to their facilities. No specific
action or response is requested at this time. If further NRC evaluations so
indicate, an IE Circular or Bulletin will be issued to recommend or request
specific licensee actions. If you have questions regarding this matter,
please contact the Director of the appropriate NRC Regional Office.
Signature
(Regional Director)
Enclosures:
1. Information Notice No. 79-01
2. List of IE Information Notices
Issued in 1979
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D. C. 20555
February 2, 1979
Information Notice No. 79-01
BERGEN-PATERSON HYDRAULIC SHOCK AND SWAY ARRESTORS (HSSA)
On December 4, 1978, Rancho Seco Nuclear Generating Station reported the
failure of seven Bergen-Paterson HSSA (Snubber) units to lockup in the
compression direction and the failure of one additional unit to lockup in
the extension direction. These failures were identified during surveillance
testing and the affected models included HSSA-3-6, HSSA-10-6 and HSSA-20-6.
When the units were disassembled, the licensee observed damage to the poppet
valve and seat on the compression side of the valve blocks of the seven
units that failed in the compression direction. It was also observed that
five of the seven units had the poppet spring entrapped between the poppet
and the seat. The licensee attributed the seven failures in the compression
direction to abusive handling during compression of the units for
installation following testing at the previous refueling outage. The cause
of the single failure in the extension direction has not been determined. In
addition to exercising greater care in reinstallation, the licensee
committed to functionally test all Bergen-Paterson snubbers subjected to
transient conditions which cause either physical damage to or significant
movement of piping. This testing will include verification of piston
movement, lockup and bleed. The Bergen-Paterson Technical Maintenance Manual
recommends that additional inspections should be made on units which may
have participated in an unusual shock occurrence involving known damage to
piping or equipment.
On January 3, 1979, the licensee reported that the decay heat removal system
had been subjected to a transient condition in the form of a "water hammer."
This transient, caused pipe movement great enough to damage two rigid pipe
support wall attachments. The subsequent functional testing of the affected
Bergen-Paterson units revealed that one of seven units failed the lockup
test. This unit (Model No. HSSA-3-6) was disassembled and damage to the
poppet valve and seat was observed.
The damage to the poppet valves is presently being reviewed by both the
licensee and Bergen-Paterson. At this time, the cause of damage has not been
completely defined nor has appropriate corrective action been determined.
Other licensees have reported instances of poppet valve damage; however, the
cause and extent of damage are not known at this time.
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Information Notice No. 79-01 February 2, 1979
This information is provided as an early notification of a possibly
significant matter. It is expected that recipients will review the
information for possible applicability to their facilities. No specific
action or response is requested at this time. If further NRC evaluations so
indicate, an IE Circular or Bulletin will be issued to recommend or request
specific licensee actions. If you have questions regarding this matter,
please contact the Director of the appropriate NRC Regional Office.
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